The reaction mixture formed in the production process of tetrafluoroethylene by the high temperature pyrolysis of monochloro-difluoromethane as described above contains various by-products in addition to TFE as the intended product. As such by-products, trifluoroethylene, difluoromethane (CH2F2, which is hereinafter referred to also as “R32”) and so on may be exemplified. Also, the reaction mixture usually contains R22 as an unreacted component.
As the process for recovering TFE from the reaction mixture, Japanese Patent Kokai Publication No. 7-233104 discloses a process which uses two distillation apparatuses. In the process, the first distillation apparatus separates the reaction product into a higher boiling point fraction which contains TFE and a lower boiling point fraction which boils at a lower temperature than TFE, and then the second distillation apparatus separates the higher boiling point fraction which contains TFE into TFE and a higher boiling point fraction which boils at a higher temperature than TFE.
The process using the distillation apparatuses as described above generally requires a reflux, and a reflux ratio thereof is large so that a large amount of energy (usually heating energy through steam) is required. Therefore, it is desirable to provide a process which reduces energy consumption so that TFE is effectively recovered.